To determine the gene expression of IFNAR1, IFNAR2 and MxA protein and the association with IFNbeta treatment response in MS patients. MS patients treated with IFNbeta had a significant decrease in IFNAR1 and IFNAR2 expression, and a significant increase in MxA compared to non-treated patients and healthy controls. Also, those patients who had a good response to treatment had a significant decrease in IFNAR1 and IFNAR2 expression compared to non-responders, non-treated patients and healthy controls. IFNbeta influences the expression of its receptors, and is greater in patients who respond to IFNbeta treatment. This down-regulation could be indicative of the response to IFNbeta.